Automated testing systems may conduct clinical chemistry or assays using one or more reagents to identify an analyte or other constituent in a biological specimen such as urine, blood serum, blood plasma, interstitial liquid, cerebrospinal liquids, and the like. For convenience and safety reasons, these specimens are almost universally contained in specimen containers (e.g., blood collection tubes). The assay or test reactions generate various changes that may be read and/or otherwise manipulated to determine a concentration of analyte or other constituent present in the specimen.
Improvements in automated testing technology have been accompanied by corresponding advances in pre-analytical sample preparation and handling operations such as sorting, batch preparation and loading, centrifugation of specimen to separate specimen constituents, cap removal to facilitate specimen access, and the like by automated pre-analytical specimen preparation systems, which may be part of a Laboratory Automation System (LAS). The LAS may automatically transport specimens contained in specimen containers to a number of pre-analytical specimen processing stations and analytical stations containing clinical chemistry analyzers and/or assay instruments.
LASs may handle a number of different specimens contained in bar code-labeled specimen containers at one time. The LAS may handle all different sizes and types of specimen containers, and they may also be intermingled. The bar code label may contain an accession number that may be correlated to demographic information that may be entered into a hospital's Laboratory Information System (LIS) along with test orders and other information. An operator may place the labeled specimen containers onto the LAS system, which may automatically transport the specimen containers for pre-analytical operations such as centrifugation, decapping, and aliquot preparation, and the like; all prior to the specimen actually being subjected to clinical analysis or assaying by one or more analyzers or instruments that may be part of the LAS. In some cases, multiple labels may be adhered to the specimen container obscuring views of the specimen.
For certain tests, a serum or plasma portion obtained from whole blood by fractionation (e.g., centrifugation) may be used. A gel separator may be added to the specimen container to aid in the separation of the settled blood portion from the serum or plasma portion in some cases. After fractionation and a subsequent de-capping process, the specimen container may be transported to an appropriate analyzer or instrument that may extract via aspiration, serum or plasma portion from the specimen container and combine the serum or plasma portion with one or more reagents in a reaction vessel (e.g., cuvette or other vessel). Analytical measurements may then be performed, often using a beam of interrogating radiation, for example, or by using photometric or fluorometric absorption readings, or the like. The measurements allow for the determination of end-point or rate values, from which a concentration of analyte or other constituent may be determined using well-known techniques.
Unfortunately, the presence of certain artifacts in the specimen, as a result of sample processing, may possibly adversely affect the accuracy of the test results of the analyte or constituent measurement obtained from the analyzer or instrument. For example, a clot in the specimen (e.g., a blood clot), which may be unrelated to the patient disease state, may cause a different interpretation of the disease condition of the patient. Further, aspiration of a clot may present other problems such as contamination or shut down time for cleaning. Presence of bubbles and/or foam may also cause a different interpretation of the disease condition of the patient.
In the prior art, the integrity of the serum or plasma portion of the specimen may be visually inspected by a skilled laboratory technician. This may involve a review of the color of the serum or plasma portion of the specimen and visual examination for clots, bubbles, and foam. A normal serum or plasma portion has a light yellow to light amber color, and may be free of clots, bubbles, and foam. However, visual inspection is very subjective, labor intensive, and fraught with the possibility of human error.
Because manual inspection includes the problems listed above, it is becoming increasingly important to evaluate the integrity of the specimen without the use of visual inspection by a laboratory technician, i.e., by using an automated pre-inspection method to the extent practical. The pre-inspection method is carried out prior to analysis at an analyzer or instrument. However, in some instances, bar code label(s) adhered directly to the specimen container may partially occlude the view of the specimen, so that there may not be clear opportunity to visually observe the serum or plasma portion of the specimen via normal automated processes.
In some systems, such as those described in US Pat. Pub. 2012/0140230 to Miller, describe rotating the specimen container to find a view window that is unobstructed by the label(s). However, such systems may be less prone to ease of automation.
Because of problems encountered when an artifact such as a clot, bubble, or foam is present within a specimen to be clinically analyzed, there is an unmet need for a method and apparatus adapted to readily and automatically determine a presence of such artifacts. The method and apparatus should not appreciably adversely affect the speed at which analytical or assaying test results are obtained. Furthermore, the method and apparatus should be able to be used even on labeled specimen containers, where one or more labels occlude some portion of the specimen.